The domestic forsythia’s yellow blooms are a harbinger of spring for many, but have you ever wondered which of Indiana’s many native shrubs is the earliest to produce flowers? There are many that flower in April and May, but a few hardy species produce some rather uninteresting-looking flowers in mid-March, or earlier, depending on weather conditions.

Probably our earliest, and certainly our most common among these cool-weather flowering shrubs, is American hazel or hazelnut (Corylus americana). It is also known as filbert, which refers to the small, tasty nut it produces. With the first warm weather in February, the male flowers that are in overwintering structures known as catkins, begin to stretch and elongate. With enough days of temperatures in the 40s, the catkins will fully elongate (4” – 5”) and the tiny female flowers emerge from separate buds along the branches. Pollen is then released by the males with the wind distributing pollen to the female flowers. Its flowering is sometimes complete a month before leaves appear.

In flower, or even while the yellowish catkins are stretching, it stands out in the landscape as it does at no other time of the year. When searching for hazelnut, look for a large shrub, up to 10 to 12 feet, that grows in multi-stemmed, dense clumps. It is commonly found in fencerows, woods edges, old pastures and other formerly disturbed areas where it prefers full sun.

Hazelnut is a member of the birch family – Betulaceae. Most members of this family have flowers (usually male) that overwinter in catkins. Another early flowering native shrub is smooth alder (Alnus serrulata), which is also a member of the birch family. Catkins are visible on branches all winter, and are quite obvious as they stretch in the spring. It flowers at nearly the same time as hazelnut, but is only found in southern Indiana and is much more particular about where it grows – wet sites only.